Radiation detection technology plays a significant role in health and safety applications. These applications include diagnostic systems used for medical imaging or non-destructive testing. Safety applications include systems used for mapping hot spots after nuclear accidents and for monitoring leakage of radioactive waste during storage or transportation. As the amount and availability of nuclear material increases throughout the world, the need to detect and identify dirty bombs and nuclear weapons places greater demands on the development of radiation detection technology.
Radioactive material, such as that used in dirty bombs or nuclear weapons, emits gamma rays. The ability to detect the presence of gamma rays and locate their source is necessary to monitor and control the movement of radioactive material. Conventional radiation detection technologies have significant disadvantages that limit this ability. For example, conventional systems based on pinhole camera designs have relatively low sensitivity since only a small portion of gamma rays emitted by a gamma ray source pass through the aperture to reach the detector. Additionally, conventional systems typically have a limited field of view which requires some prior knowledge on the general location of the gamma ray source in order to detect and locate it. In situations where a number of cargo containers, cars, baggage, persons, etc. are being monitored, conventional radiation detection systems often involve inspecting each potential carrier individually in close proximity to the detection system. This arrangement strains available resources and is not ideal in areas where a large number of potential carriers are passing through.